1. Field of the Invention
The present invention relates to a spark leakage shutoff protective device and, more particularly, to a spark leakage shutoff protective device for a plug.
2. Description of the Related Art
A spark leakage shutoff protective device is mounted in a plug to shut the electric power of the plug when spark leakage occurs so as to provide a protective effect to the plug. The plug has at least two legs.
A conventional spark leakage shutoff protective device 10 in accordance with the prior art shown in FIGS. 5–7 comprises an upright flexible snapping lever 14 mounted on the plug (not shown) and having a distal end formed with a snapping hook 140, a voltage detection electromagnetic valve 11 mounted on the plug, and a restoring member 12 having a first end detachably mounted on the snapping hook 140 of the snapping lever 14 and a second end driven by the voltage detection electromagnetic valve 11 to move the restoring member 12 so that the restoring member 12 is movable between a first position as shown in FIG. 6 where the first end of the restoring member 12 is snapped onto the snapping hook 140 of the snapping lever 14 and a second position as shown in FIG. 7 where the first end of the restoring member 12 is detached from the snapping hook 140 of the snapping lever 14. The snapping hook 140 of the snapping lever 14 has a tapered shape and is arranged from an outside toward an inside thereof. The restoring member 12 is located between the voltage detection electromagnetic valve 11 and the snapping lever 14.
In operation, when the voltage detection electromagnetic valve 11 detects that the spark leakage occurs, the second end of the restoring member 12 is driven by the voltage detection electromagnetic valve 11 to move the restoring member 12 so that the first end of the restoring member 12 is detached from the snapping hook 140 of the snapping lever 14 as shown in FIG. 7, to shut the electric power of the plug so as to provide a protective effect to the plug.
However, the snapping lever 14 is located outside of the restoring member 12 so that the snapping lever 14 is closer to the legs of the plug. Thus, the snapping lever 14 is easily deformed or worn out due to a higher temperature of the legs of the plug, thereby decreasing the lifetime of the snapping lever 14. In addition, the snapping lever 14 is subjected to a stress from the restoring member 12, and the stress is concentrated on the root portion of the snapping lever 14, so that the snapping lever 14 is easily deformed or worn out due to the stress concentration during a long-term utilization, thereby affecting operation of the snapping lever 14.